1. Field of the Invention
The present invention generally relates to an integrated circuit card of the type wherein an integrated circuit is mounted within a card such as a credit/debit card, a bank card, an identification card, a medical card, etc., and, more particularly, to rendering such a card shock resistant to forces tending to deform the card.
2. Description of the Prior Art
It has been proposed in the prior art to embed an integrated circuit module or like electrical device within a conventional plastic card such as a credit/debit card, a bank card, an identification card, a medical card, and the like, to constitute an integrated circuit card or a so-called "smart" card. The integrated circuit module may be programmed or programmable, with a set of instructions for controlling the use of the card. The integrated circuit module may also have a memory in which data may be stored and from which data may be retrieved.
Although generally satisfactory for its intended purpose, such an integrated circuit card has not proven to be altogether reliable in practice. Such cards are typically carried by a user in his or her pocket and/or in a wallet or purse and, hence, are frequently subjected to various externally directed forces which act to bend, twist, push and pull the card, thereby tending to deform the card. Experience has shown that, over time, the integrated circuit module will become detached or broken loose from the card, or various electrical connections of the module will be broken, thereby rendering the card inoperative.
By way of example, reference is directed to FIGS. 4 and 5 of the patent drawings wherein a conventional integrated circuit card 100 of the prior art is shown. The card 100 is flattened and generally rectangular in shape, and has a pair of long sides 2 extending along a longitudinal direction, and a pair of short sides 3 extending along a transverse direction perpendicular to the longitudinal direction. The card 100 has rounded corners where the sides 2, 3 meet. The card 100 also has a longitudinally-extending axis of symmetry extending lengthwise of the card centrally between the short sides 3, as well as two opposite generally planar exterior major surfaces.
As best shown in FIG. 5, the card 100 includes a central body or carrier 5 having an upper overlay film 6 on an upper one of the exterior major surfaces, and another lower overlay film 7 on the lower of the exterior major surfaces of the card. A magnetic tape stripe 8 is applied on and/or embedded in the upper overlay film 6, and extends longitudinally between the short sides 3 along a marginal edge region of the card in a direction parallel to either of the long sides 2. The marginal edge region is adjacent to one of the long sides 2.
An integrated circuit module including an integrated circuit or chip 4 is embedded in the carrier 5, and has a plurality of exterior terminals 1 which are exposed through an opening formed in the upper overlay film 6 at the upper major surface of the card to the exterior thereof. The exterior terminals 1 provide access to the chip 4. The chip 4 and its exterior terminals 1 which are located directly above the chip 4 are positioned on the card generally near one longitudinal end of the card as considered with respect to the longitudinal direction and, as shown in FIG. 4, near the left end of the card. The chip 4 and its exterior terminals 1 are also positioned generally near the center of the card as considered with respect to the transverse direction and,as shown in FIG. 4, between the magnetic stripe 8 and the longitudinal axis of symmetry.
Thus, as previously discussed, when the conventional card 100 is subjected to forces tending to deform the card, particularly when such forces bend the card about a central axis, such forces are concentrated in magnitude at or near the center of the card and in the vicinity of the chip 4. Thus, the forces applied at the chip and around its perimeter are high in magnitude and tend to separate the chip, which has a relatively stiff, rigid characteristic as compared to the more flexible plastic carrier, from the carrier. Over time, the chip can actually become detached from the carrier. Also, the relatively large stress forces concentrated in the circumambient region of the chip and at the exterior terminals 1 tend to crack those portions of the upper overlay film 6 which surround the exterior terminals 1. Such cracks shorten the useful working lifetime of the card.